Secondary rear surface touch sensor for handheld device

Abstract

The invention relates to a secondary rear surface touch sensor for a handheld device. A second touch area (314) is provided in a position on the rear side of the mobile phone (300) such that an index finger of a hand can provide input while the hand is holding the mobile phone (300). Various types of inputs provided using the second touch area (314) do not require the other hand. This allows the mobile phone (300) to be used in many cases in a single hand operation.

Description

[0001] Related application information

[0002] This application is a divisional application. The parent application of this divisional application is the invention patent application case with the application date of October 16, 2019, the invention name of “Secondary back surface touch sensor of handheld device”, and the application number of 201980068434.6. TECHNICAL FIELD

[0003] The present invention relates to input methods for handheld devices. BACKGROUND

[0004] In the past few years, mobile phones have seen tremendous development. Many mobile phones have a front side with a large touch screen. This large touch screen allows for very complex and delicate input methods to be used, such as virtual keyboards, multi-finger touch, etc. However, another general trend among mobile phones is to become larger and larger. This makes it more difficult to hold the phone and to try to operate the phone with one hand. Therefore, to operate a mobile phone, a user needs to use two hands, one to hold the phone and one to provide input. This can be cumbersome in many situations. SUMMARY

[0005] A second touch area is provided in a position on the back side of the mobile phone such that the index finger of the hand that is holding the mobile phone can provide input while that hand is holding the mobile phone. Various types of input provided using this second touch area do not require the use of the other hand. This allows the mobile phone to be operated with one hand in many situations. BRIEF DESCRIPTION OF DRAWINGS

[0006] Figure 1 is a block diagram of an example mobile phone.

[0007] Figure 2 is a block diagram of a capacitive touch system.

[0008] Figure 3 is a back view of a mobile phone illustrating example positions of example capacitive touch sensors.

[0009] Figure 4 is a top view of the capacitive touch sensor of Figure 3

[0010] Figure 5 is a view showing an internal view of the back cover of the mobile phone of Figure 3

[0011] Figure 6A is a cross-sectional view of the back cover of the mobile phone of Figure 3

[0012] Figure 6B is a cross-sectional view of the back cover of the mobile phone of Figure 6A ​​​a cross-sectional view of a mobile phone with a first example case attached to the mobile phone.

[0013] Figure 6C is Figure 6A a cross-sectional view of a mobile phone with a second example case attached to the mobile phone.

[0014] Figure 6D is Figure 6C a rear view of a mobile phone and a second example case.

[0015] Figure 6E is Figure 6A a cross-sectional view of a mobile phone with a third example case attached to the mobile phone.

[0016] Figure 7 is a rear view of a mobile phone illustrating an example location of a second example capacitive touch sensor that allows right and left hand operation.

[0017] Figure 8 is a rear view of a mobile phone illustrating an example location of a third example capacitive touch sensor.

[0018] Figure 9 is a rear view of a mobile phone illustrating an example location of a fourth example capacitive touch sensor that allows right and left hand operation.

[0019] Figure 10 is an operational flowchart for calibrating a rear side touch sensor. DETAILED DESCRIPTION

[0020] Figure 1A block diagram illustrates an example mobile phone 100. The mobile phone 100 can include a phone system on chip (SOC) 102. The phone SOC 102 includes multiple processors 104, a large amount of RAM 106, and a long term evolution (LTE) modem 108. This is a very simple illustration of an example phone SOC and many other variations can be used with some of the components off board, e.g., a modem. A power subsystem 110 provides power to the phone SOC 102. A battery 112 provides power to the power subsystem 110. A USB port 114 is provided for external wired communication with the phone SOC 102. A large dynamic RAM (DRAM) 116 is provided as main storage storage, with the internal RAM 106 more used as operating memory for the various processors 104. A display 118 is connected to the phone SOC 102 to provide the main front view of the mobile phone 100. A front touch sensor system 120 is connected to the phone SOC 102 and overlaid on the display 118, with a separate processor operating the touch sensor. A speaker 122 provides audio output for the mobile phone 100, while a microphone 124 provides audio input to the phone SOC 102. A subscriber identity module (SIM) 126 is connected to the phone SOC 102 to provide personalization information. A radio frequency (RF) section 128 is connected to the phone SOC 102 to perform the actual wireless transmission in the mobile phone. Flash memory or non-volatile memory is connected to the phone SOC 102 to store programs executed by the processors 104. A string of buttons 130 are connected to the phone SOC 102 as needed, e.g., power button, volume buttons, etc. A back side touch sensor system 132 is connected to the phone SOC 102 to provide a back side touch system on the mobile phone 100.

[0021] Figure 2is a block diagram of the back side touch sensor system 132. The touch sensor controller 200 is the computational portion of the back side touch sensor system 132. A processor or CPU 202 is provided in the touch sensor controller 200 to perform the necessary computations. A non-volatile memory 204 that stores the programs executed by the CPU 202 is connected to the CPU 202. A RAM 206 is also connected to the CPU 202 to be used as a working memory. An analog to digital converter (ADC) section 208 is provided to allow the back side touch sensor system 132 to perform analog operations. An input output (I / O) port 210 is provided and connected to the CPU 202 to allow the CPU 202 to interface with the phone SoC 102. Most relevant to this discussion, a capacitive touch interface 212 is connected to the CPU 202 to perform the analog operations for capacitive touch sensing. A back side touch sensor area 214 is connected to the capacitive touch interface 212. In normal operation, the touch sensor controller 200 provides the position of the user's index finger over or relative to the back side touch sensor area 214 to the phone SoC 102 to allow control of the mobile phone 100. The MSP430FR2633 capacitive touch sensing mixed-signal microcontroller from Texas Instruments is an example of the back side touch sensor controller 200.

[0022] Figure 3 A back view of an example mobile phone 300 is illustrated. The mobile phone 300 has a top 304, a bottom 306, a right side 308 (when viewed from the front), and a left side 310. An opening 302 is provided in the back cover or plate 301 to allow for a camera and related optical components. Other openings can be provided, such as for a power button or fingerprint sensor. Shown by the dashed line is the back side touch sensor 314 of the mobile phone 300. The back side touch sensor 314 is shown in dashed lines and is located behind the back cover 301 of the mobile phone 300. Again, the back side touch sensor 314 is located on the back of the mobile phone 300. The back side touch sensor 314 is located on the back of the mobile phone 300. Figure 3 If the mobile phone 300 is held in the right hand of an individual and the top 304 of the mobile phone 300 is in the upward direction, the back side touch sensor 314 is positioned so that the user's index finger can easily swipe over the back side touch sensor 314. The arcuate shape of the back side touch sensor 314 is conformal to the path that the user's fingertip slides over. This allows the user to use the secondary input when holding the phone in one hand and does not require the use of the other hand.

[0023] Figure 4The back side touch sensor 314 is explained in more detail. The printed circuit board 402 has a series of electrodes or traces 404, 406, 408, 410, 412, 414, 416, 418, and 420 on the surface of the printed circuit board 402. The traces 406 through 420 are configured in the illustrated example as a mutual capacitive touch sensing configuration. A self-capacitance sensing configuration can also be utilized. A flexible cable 422 with a series of contacts 424 is connected to the printed circuit board 402 to allow electrical connection between the touch sensor controller 200 and the printed circuit board 402.

[0024] Figure 5 is a view of the back cover 301 of the mobile phone 300, which is viewed from the inside of the mobile phone 300 so that the capacitive sensor PCB 402 and cable 422 can be easily observed when mounted to the back cover 301.

[0025] Figure 6A illustrates a cross-sectional view of the back cover 301 with the printed circuit board 402, where the various traces 406 through 420 are attached as illustrated. In this arrangement, the traces 406 through 420 are very close to the outside or back of the mobile phone 300 and thus operate at a lower gain level due to the higher sensitivity of the configuration. In Figure 6B In the case of the case 600 added to the mobile phone 300, where the case 600 covers over the back cover 301 to protect the mobile phone 300 extensively. As shown, this increases the distance of the user's finger from the traces 406 through 420. Depending on the thickness and electrical properties of the protective material of the case 600, the sensitivity of the back side touch sensor system 132 and Figure 6A may change, for example, due to increased conversion gain or counting, compared to the caseless example of Figure 6C An alternative case 602 is shown. The case 602 includes an external ridge or curvilinear finger guide 604, as Figure 6D As shown in the case 600, the external ridge or curvilinear finger guide 604 generally indicates or outlines the back side touch sensor 314 to allow the user to easily align their index finger with the back side touch sensor 314. Figure 6E A third example case 606 is illustrated in the case 606. In the case 606, instead of the external ridge 604 used in the case 602, the case 606 has an open or cutout area 608 that generally indicates or is conformal with the back side touch sensor 314. This allows both user index finger alignment and increased sensitivity or reduced gain, as now the cover thickness and material do not block the capacitive sensors.

[0026] Figure 7FIG. illustrates a mobile phone 700 with a capacitive touch sensor area 702 that is generally formed as a 180° arc instead of a 90° arc of the back side touch sensor 314. This allows the touch sensor area to be used with left hand operation or right hand operation, thus reducing the number of phones that need to be developed, produced, and inventoried.

[0027] Figure 8 FIG. illustrates an example phone 800 in which the arcuate back touch sensor 314 is replaced by an area sensor 802. By using an area sensor 802, two-dimensional movement of a user's index finger can be easily detected compared to the curvilinear one-dimensional operation of the back side touch sensor 314. This allows improved user control, although not as precise as using a front touch system. Figure 9 FIG. illustrates a mobile phone 900 with an area sensor 902 suitable for left hand operation and right hand operation.

[0028] Figure 10 is a flowchart 1000 of the operation of calibrating the back side touch sensor system 132. As discussed above, in some examples, the mobile phone can have a case installed to protect the mobile phone. The protective material of the case and the proximity (or lack of proximity) of the case back cover change the capacitive properties of the back side touch sensor system 132 such that recalibration is necessary. In step 1002, a user interface (UI) is displayed to provide user instructions for the calibration process. In step 1004, the user is instructed to place their finger over the back side touch sensor. In step 1006, the user is instructed to start moving their finger along the back side touch sensor. In step 1008, initial adjustments are made to touch sensitivity parameters. These parameters include conversion gain and conversion count. In step 1010, it is determined whether satisfactory movement of the user's finger is detected. If not, then in step 1012, it is determined whether the parameter adjustments have reached maximum sensitivity. If maximum sensitivity is reached, then in step 1014, an error message is displayed to the user indicating that the calibration has failed. If maximum sensitivity has not been reached, then the operation returns to step 1008 for the next adjustment of the sensitivity parameters.

[0029] If satisfactory movement is detected in step 1010, then in step 1016, the sensitivity parameters are stored for continued use. In step 1018, the user is informed that they can stop finger movement and that the calibration is complete.

[0030] The illustrated capacitive touch sensor configuration is an example, and other specific designs can be varied. For example, self-capacitance or mutual capacitance configurations can be used. Different configurations and numbers of PCB traces can be used. Alternative sensor areas and shapes can be used. For example, instead of the illustrated 90° arc, larger or smaller arcs can be used, where the arcs begin or end at different locations.

[0031] This description uses the movement of a user's finger as an example touch action. Other touch actions, such as double-tap or multi-finger gestures, can also be recognized. For example, a user's double-tap on the rear touch sensor can be used to answer a phone call or respond to a request presented on the front screen. This description also uses the index finger as an example finger for interacting with the touch sensor. Other fingers or the thumb (considered the finger for this application) can also be used, especially in cases where the permitted action is only a click rather than full motion.

[0032] This explanation is based on information from Texas Instruments and CapTIvate. TM A more complete explanation can be provided using a microcontroller for the technology, but other touch-sensing microcontrollers and technologies can be used. Alternatively, a touch sensor with an embedded processor can be used, but one of the processors in the handheld device can provide the processing functionality in place of the embedded processor.

[0033] While a mobile phone is used as an example of a handheld device, the rear touch sensor can be used on other handheld devices.

[0034] Modifications may be made to the described embodiments, and other embodiments may be possible within the scope of the claims.

Claims

1. An electronic device comprising: Capacitive sensors, including: Printed circuit boards; The first electrode is disposed on the printed circuit board and has a curved shape; The second electrode is disposed on the printed circuit board and has a curved shape; and A set of electrodes disposed between the first electrode and the second electrode on the printed circuit board.

2. The electronic device of claim 1, wherein each of the set of electrodes has a substantially triangular shape.

3. The electronic device of claim 1, wherein the capacitive sensor further comprises a cable including a set of contacts.

4. The electronic device according to claim 3, further comprising: A sensor controller, which is coupled to the capacitive sensor via the set of contacts of the cable.

5. The electronic device according to claim 1, further comprising: The front side includes the display; and The rear side is disposed opposite to the front side containing the capacitive sensor.

6. The electronic device of claim 5, wherein the rear side includes a housing, and the capacitive sensor is disposed on the housing.

7. The electronic device of claim 6, wherein the housing includes a protrusion extending from the remainder of the housing, which is opposite to and aligned with the capacitive sensor.

8. The electronic device of claim 6, wherein the housing includes a groove aligned with the capacitive sensor.

9. A mobile device comprising: processor; A first touch sensor, coupled to the processor, comprises: Printed circuit boards; The first electrode is disposed on the radially inward portion of the printed circuit board and has a curved shape; The second electrode is disposed on the radially outward portion of the printed circuit board and has a curved shape; and A set of electrodes disposed between the first electrode and the second electrode on the printed circuit board; and A second touch sensor is coupled to the processor.

10. The mobile device of claim 9, further comprising a touchscreen, the touchscreen including the second touch sensor, wherein: The touchscreen is disposed on the front side of the mobile device; and The first touch sensor is located on the rear side of the mobile device, opposite to the front side.

11. The mobile device according to claim 9, wherein each of the set of electrodes has a substantially triangular shape.

12. The mobile device of claim 9, further comprising a housing, wherein the first touch sensor is disposed on the inner surface of the housing.

13. The mobile device of claim 12, wherein the housing includes a bulge on the outer surface of the housing, the bulge extending from the remainder of the housing and opposite to and aligned with the first touch sensor.

14. The mobile device of claim 12, wherein the housing includes a groove aligned with the first touch sensor.

15. The mobile device of claim 9, further comprising a mobile phone chip system including the processor.

16. A mobile phone device comprising: Mobile phone chip system; A display located on the front side of the mobile phone device and coupled to the mobile phone chip system; and A touch sensor, located on the back of the mobile phone device and coupled to the mobile phone chip system, wherein the touch sensor includes: First curved electrode; Second curved electrode; and A set of electrodes is disposed between the first curved electrode and the second curved electrode.

17. The mobile phone device of claim 16, wherein the touch sensor has an arcuate shape.

18. The mobile phone device of claim 16, wherein each of the set of electrodes has a substantially triangular shape.

19. The mobile phone device of claim 16, wherein the back surface of the mobile phone device includes a raised portion aligned with the touch sensor.

20. The mobile phone device of claim 16, wherein the back surface of the mobile phone device includes a recess aligned with the touch sensor.

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